In recent years, rapid processing at high temperature has rapidly been popularized in a developing step of a photographic material (hereinafter referred to as a light-sensitive material). Also in a processing of various light-sensitive materials with an automatic developing machine, a processing time thereof has been shortened to a large extent. In order to achieve the rapid processing, there are needed a developing solution capable of providing sufficient sensitivity in a short time and a light-sensitive material having an excellent development accelerating property and capable of providing a sufficient photographic density in a short time. Efficient as a method for increasing an activity of a developing solution are a method in which the amounts of a developing agent and an auxiliary developing agent each contained in a developing solution are increased, a method in which pH of a developing solution is raised, and a method in which a processing temperature is raised. However, either of these methods has the problems that stability of a processing solution in storage is deteriorated and that a gradation decreases and a fog increases.
The techniques for utilizing tabular grains for the purpose of improving the above matters are described in U.S. Pat. Nos. 4,439,520 and 4,425,425. Further, there are described in JP-A-63-305343 (the term "JP-A" as used herein means an unexamined published Japanese patent application) and 1-77047, the techniques for improving a development accelerating property and a sensitivity/fog ratio by making development initiation points of a silver halide grain be only at its peak and/or ridgeline, or vicinity thereof. However, these techniques are still insufficient, and it has been desired to attain an excellent development accelerating property and a low fog while maintaining a high sensitivity.
A silver halide emulsion is usually subjected to a chemical sensitization with various chemical substances in order to obtain desired sensitivity and gradation. There are known as a representative method therefor, a sulfur sensitization, a selenium sensitization, a noble metal (for example, gold) sensitization, a reduction sensitization, and various sensitization methods in which the above sensitizations are combined.
In recent years, there are strong demands for high sensitivity, excellent graininess and high sharpness in a silver halide photographic material as well as rapid processing in which a development processing is expedited, and various improvements in the above sensitizing methods have been made.
Of the above sensitizing methods, the selenium sensitization is disclosed in U.S. Pat. Nos. 1,574,944, 1,602,592, 1,623,499, 3,297,446, 3,297,447, 3,320,069, 3,408,196, 3,408,197, 3,442,653, 3,420,670, and 3,591,385, French Patents 2,693,038 and 2,093,209, JP-B-52-34491 (the term "JP-B" as used herein means an examined Japanese patent publication), 52-34492, 53-295, and 57-22090, JP-A-59-180536, 59-185330, 59-181337, 59-187338, 59-192241, 60-150046, 60-151637, and 61-246738, JP-A-3-4221, 1-287380, 1-250950, 1-254441, 2-34090, 2-110558, 2-13097, 2-139183, and 2-229300, British Patents 255,846 and 861,984, and Journal Photographic Science, Vol. 31, pp. 158 to 169 (1983), written by H. E. Spencer et al.
While a selenium sensitization generally has a larger sensitizing effect than a sulfur sensitization usually applied in the art, it has a marked tendency of liability to cause much fog and soften a gradation. A large part of the above published patents improves the above defects but the results obtained are still insufficient. In particular, the basic improvement for controlling generation of fog has been intensively desired. In particular, the combination of a gold sensitization with a sulfur sensitization or with a selenium sensitization can provide a marked increase in sensitivity but at the same time the increase in fog is accompanied. The gold-selenium sensitization particularly increases a fog as compared with the gold-sulfur sensitization. Accordingly, there has been intensively desired development of the selenium sensitization in which a sensitivity change in storage is controlled and the generation of fog is suppressed. It is still more difficult to attain a merit of a high sensitivity with the above combination further with a reduction sensitization since it accelerates generation of fog. Further, in a chemical sensitization of tabular grains, it is difficult to control the chemical sensitization because a surface area thereof per volume is large, which results in the most difficulty to control generation of fog while increasing a sensitivity.
A light-sensitive material has been desired to be more sensitive and to be able to be rapidly processed, and therefore it has attempted to increase the sensitivity of a silver halide emulsion used therefor and accelerate the processing by reducing a binder amount. However, the increase in sensitivity to light and the reduction of the amount of binder (gelatin and a high molecular weight polymer) which serves as a protective colloid worsen properties of a light-sensitive material with respect to stress blackening and scratch-blackening. Further, generation of fog and desensitization during storage of a light-sensitive material are liable to take place as well.
There is a method known in the art that the blackening can be reduced by incorporating hydroquinone or a derivative thereof into a layer constituting a light-sensitive material, as described in, for example, JP-A-64-72141. Also, it is described in, for example, JP-A-2-280457 that hydroquinone having an adsorbing group for making it easy to adsorb to a silver halide grain and hydroquinone having an anti-diffusion group for improving an anti-diffusion property are effective for the purpose. Further it is described in, for example, JP-A59-97134 that a triazine compound and a derivative thereof are particularly effective for improving storability of tabular grains.
However, a hydroquinone compound and a derivative thereof are often used as a developing agent because of its high reducing property against Silver halide. Accordingly, it is supposed that silver in a high sensitive emulsion subjected to a chemical sensitization with a selenium sensitizer is reduced during storage and that an aging fog is liable to cause, as described in Theory of Photographic Process, Vol. 4, written by T. H, James et al.